Self Locking Racket Stringing Machine Tensioner

ABSTRACT

An automatically braking tensioner for a racket stringing machine is disclosed. The tensioner comprises a tensioner housing, a drum connected to the tensioner housing, a string gripper connected to the drum, a disk brake having an axle extending from an axis of the disc brake, a lever disposed in the tensioner housing, and a brake lever disposed in the tensioner housing. The disk brake is connected to a stringing machine body and is rotably stationary relative to the stringing machine body. As the tensioner is rotated about the disk brake, the brake lever is engaged with the disk brake when the tensioning force is equal to a desired force which can be established my means of a compression spring. In some embodiments the tension can be altered by varying the tension or position of the spring.

FIELD OF THE INVENTION

The invention relates generally to a tennis racket stringing machine and more specifically to a self-locking tensioning arm of a tennis racket stringing machine.

BACKGROUND OF INVENTION

Tennis rackets are strung with the use of a stringing machine. A machine which can be utilized to string to tennis rackets is disclosed in U.S. Pat. No. 9,067,111 (Zdrazilla) the disclosure of which is fully incorporated herein.

During the stringing process it becomes difficult to maintain proper tension on a racket string while tying off a string. A user must lock a string in place with the proper tension when stringing a racket by hand. When a user releases a string to tie it in place, the tension is released and the string may no longer have the proper tension. This results in a racket with a loose string bed. What is needed is a tensioner arm for a tennis racket stringing machine that automatically locks into place once proper tension is placed on a string and which does not create slack in the string when locked in place.

In addition, manual racket stringing machines generally are designed to apply tension to a string with either (1) a crank tensioning device where the operator pulls the string with a crank mechanism until proper tension is applied or (2) a lever tensioning device where a user balances a weight on a simple lever against the string. The crank mechanism is unwieldy and can be expensive to include on a machine. Likewise, the use of a weight, while simpler in design, is even heavier due to the need of the weight to provide the necessary tension. These tensioning methods are thus imperfect. What is needed therefore, is a simple and practically weightless means of applying tension to a string during the stringing process.

SUMMARY OF THE INVENTION

The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed innovation. This summary is not an extensive overview, and it is not intended to identify key/critical elements or to delineate the scope thereof. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

The invention is directed toward an automatically braking tensioner for a racket stringing machine. The tensioner comprises a tensioner housing, a string gripper connected to the tensioner housing, a disk brake having an axle extending from an axis of the disc brake, a lever disposed in the tensioner housing, and a brake lever disposed in the tensioner housing. The disk brake is connected to a stringing machine body and is rotably stationary relative to the stringing machine body. The disk brake has a lip disposed laterally from the disk brake. The lever has a first end and a second end, the first end having an aperture. The axel of the disk brake is disposed through the aperture. The brake lever has a first end and a second end, the first end having a channel disposed laterally into the brake lever. The lip of the disk brake is disposed within the channel of the brake lever.

The tensioner may further comprise a cam connected to the lever. The cam has a varying diameter about the cam. The external perimeter of the cam is adjacent to the second end of the brake lever. When the cam rotates about a cam axis, the external perimeter of the cam displaces the second end of the brake lever.

The tensioner may further comprise an axial spring having a first end connected to the lever and a second end connected to the cam and an axial spring plate. The tensioner may further comprise a stop connected to the lever and extending laterally from the lever and wherein the stop is disposed within a notch in the cam, preventing the cam from rotating about the cam axis when the stop is disposed within the notch. The tensioner may further comprise a pin having a first end connected to the cam and a second end disposed adjacent to the first end of the brake lever.

The tensioner may further comprise a slidable spring assembly and a slot disposed in the tensioner housing. The slidable spring assembly is configured to slide along a length of the lever and a portion of the slidable spring assembly extends through the slot.

In another embodiment the spring utilized may be a compression spring which is in a fixed position between the lever and the tensioner housing. A user may alter the tension by turning a knob connected to the end of the compression spring with the other end of the compression spring being attached in a fixed position.

In another embodiment of the invention, the slidable spring assembly further comprises a spring housing, a compression spring disposed within the spring housing, and a spring support pad disposed at an end of the spring. The spring support pad is disposed adjacent to the lever. In another embodiment of the invention the cam further comprises a brake release extending from the cam and disposed through an aperture in the tensioner housing.

Still other embodiments of the present invention will become readily apparent to those skilled in this art from the following description wherein there is shown and described the embodiments of this invention, simply by way of illustration of the best modes suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modifications in various obvious aspects all without departing from the scope of the invention. Accordingly, the drawing and descriptions will be regarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of this invention will be described in detail, wherein like reference numerals refer to identical or similar components, with reference to the following figures, wherein:

FIG. 1A is a top perspective view of a tensioner arm;

FIG. 1B is a bottom perspective view of the tensioner arm;

FIG. 1C is a side view of the tensioner arm;

FIG. 1D is an end view of the tensioner arm;

FIG. 2 is a side view of the internal components of the tensioner arm;

FIG. 3A is a top perspective view of a brake lever;

FIG. 3B is a side view of the brake lever;

FIG. 4A is a top perspective view of a disk brake;

FIG. 4B is a bottom perspective view of the disk brake;

FIG. 4C is a top plan view the disk brake;

FIG. 5 is side perspective view of the internal components of the tensioner arm; and

FIG. 6 is an exploded view of the tensioner arm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The claimed subject matter is now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. It may be evident, however, that the claimed subject matter may be practiced with or without any combination of these specific details, without departing from the spirit and scope of this invention and the claims.

Referring to FIG. 1A to FIG. 6, the preferred embodiment of the self-locking tensioner 100 is illustrated. The tensioner 100 is connected to a base 200 of a tennis racket stringing machine. The tensioner 100 has a string gripper for holding a tennis racket string during the stringing process. The tensioner 100 has an axel 104 which is fastened to the base 200 of the stringing machine. The axel 104 is stationary and fixed in place relative to the base 200 of the stringing machine. The body of the tensioner 100 rotates about the axel 104. To provide the proper amount of tension to the string the tensioner 100 may utilize any known force creating means. In the preferred embodiment the tensioner 100 utilizes a slidable spring system as described in U.S. Pat. No. 9,067,111 (Zdrazilla). Once the proper tension is applied to the string the body of the tensioner 100 locks into place, preventing over tensioning. To unlock the tensioner 100 after the user has locked the string in place, the user pulls on the brake release 106.

Referring to FIG. 2, a side view of the internal components of the tensioner 100 are illustrated. The tensioner 100 has a lever 108 which floats within the internal compartment of the tensioner 100. The lever 108 rotates about the axel 104 independently from the rest of the tensioner 100. The lever 108 may be any size and shape. Disposed on top side of the lever 108 is a brake lever 110. The brake lever 110 may be any size and shape. In the preferred embodiment the brake lever 110 is a long rectangular member having one end resting on a cam 120 and the other end connected to a disk brake 114.

Referring to FIG. 3A and FIG. 3B, the preferred embodiment of the brake lever 110 is illustrated. The brake lever 110 is a long rectangular member having two ends. One end of the brake lever 110 has a channel 112. The channel 112 connects with the disk brake 114.

Referring to FIG. 4A, FIG. 4B, and FIG. 4C, the preferred embodiment of the disk brake 114 is illustrated. The disk brake 114 is connected a round circular member. The disk brake 114 has a lip 116 extending around the outer circumference of the disk brake 114. The lip 116 extends upward from the body of the disk brake 114 and defines an inner recess 118. The center of the disk brake 114 is connected to the axel 104. The axel 104 and complete body of the disk brake 114 is immovable and stationary relative to the base 200 of the stringing machine. In this manner, the tensioner 100 and all of the other components, including the lever 108 and brake lever 110 rotate about the disk brake 114 during use.

Referring to FIG. 5, an enhanced view of the internal components of the tensioner is shown. As illustrated, the lip 116 of the disk brake 114 is disposed within the channel 112 of the brake lever 110. The shape of the channel 112 is complementary to the shape of the lip 116. The shape of the channel 112 and the shape of the lip 116 may be any shape provided that the channel 112 can slide rotably along the lip 116. In the preferred embodiment the channel 112 is a rectangular recess and the lip 116 is a rectangular extension. When the brake lever 110 is properly aligned to the disk brake 114, the channel 112 slides along the lip 116. When the brake lever 110 goes out of proper alignment then the edges of the channel 112 contact the edges of the lip 116. The misalignment causes a frictional force between the channel 112 and the lip 116, causing the brake lever 110 to lock in place on the disk brake 114.

As the user moves the body of the tensioner 100 the brake lever 110 rotates about the disk brake 114, with the channel 112 sliding freely about the lip 116. When the desired amount of force is exerted on tensioner 100, the lever 108 moves upward in the inner cavity of the tensioner 100. The upward movement of the lever 108 releases the fixed position of the cam 120. The cam 120 rotates in a clockwise (from the point of view illustrated) motion about an axis, lifting the end of the brake lever 110. The cam 120 pushes the brake lever 110 out of alignment, locking the brake lever 110 in place on the disk brake 114. Once the brake lever 110 is locked into place on the disk brake 114, the tensioner locks into place. When the brake lever 110 is locked, the tensioner 100 is unable to rotate backward to relieve the tension in the string. A user can push harder on the tensioner 100 and exert additional tension on the string. When doing this the user need only overcome the force of friction formed between the brake lever 110 and the disk brake 114. This operation provides enhanced benefit to users who need to add additional tension to the last string during the stringing process since tension is always lost while tying the last string. Otherwise, if the user does not exert additional force on the tensioner 100, then the tensioner 100 locks into place and does not rotate in either direction about the axel 104. When the cam 120 is activated the brake release 106 moves toward the end of the tensioner 100 with the axel 104. To unlock the tensioner 100 the user moves the brake release 106 back to its original position, moving the cam 120 to its original position. The brake release 110 moves back into alignment and the channel 112 can move freely about the lip 116.

Referring to FIG. 6, an exploded view of the components of the tensioner 100 are illustrated. The tensioner 100 comprises a left handle body 138 and a right handle body 140. The left handle body 138 and right handle body 140 are the external housing of the tensioner 100 and may be any size and shape. In the preferred embodiment the left handle body 138 and right handle body 140 are elongate members, which when connected together define an internal compartment to house the additional components of the tensioner 100. The left handle body 138 and the right handle body 140 may be connected to each other by any means. In the preferred embodiment the left handle body 138 and the right handle body 140 are secured together by a number of screws or bolts. In other embodiments adhesives may be utilized. Connected to the top side of the tensioner 100 is the string gripper 102. The string gripper 102 is used to hold onto the string during the stringing process.

The tensioner 100 also comprises a left drum section 134 and a right drum section 136. The left drum section 134 and a right drum section 136 house the disk brake 114. The left drum section 134 and a right drum section 136 may be connected by any means. In the preferred embodiment the left drum section 134 and a right drum section 136 are secured together by a number of screws or bolts. In other embodiments adhesives may be utilized. The left drum section 134 and the right drum section 136 are connected together to form a single drum. The drum is configured such that the end of the lever 108 is connected to the drum. In addition the string gripper 102 is connected to the drum. Thus as the lever 108 rotates about the axel 104, the drum is rotated about the axel 104, and the string gripper 102 is moved away from or toward the racket. The axel 104 of the disk brake 114 extends through central apertures of the left drum section 134 and a right drum section 136 to connect to the base 200 of the stringing machine. When the user tightens a string, the user pushed down on the tensioner 100 which rotates the lever 108 about the axel, rotating the drum and the string gripper 102. The string gripper 102 pulls the tension on the string. The drum is configured so that it has a constant circumference about the axel 104. As the tensioner 100 rotates the string is pulled along the drum. The drum may have a groove in which the string is placed during the stringing method so that the string is not displaced laterally during stringing.

The tensioner 100 utilizes a slidable spring assembly to set the proper amount of tension to the string. Within the tensioner 100 is the lever 108. Resting on top of the lever 108 is the slidable spring assembly. The slidable spring assembly comprises a spring housing 132, a compression spring 130, and a spring support pad 128. The spring support pad 128 rests atop the top edge of the lever 108 and can slide along the length of the lever 108. The spring 130 is disposed within the spring housing 132. The spring 130 is disposed such that one end of the spring 130 rests on the spring support pad 128 and the other end of the spring 130 contacts the top inside edge of the spring housing 132. The spring housing 132 has a set of recesses ending upward from the bottom edge to permit the lever 108 to extend into the inner compartment of the spring housing 132. As the lever 108 moves into the spring housing 132, the lever 108 pushes the spring support pad 128 upward into the spring housing 132, compressing the spring 130.

In other embodiments the spring assembly may be utilized in any configuration. In one embodiment the slidable spring assembly only includes a compression spring 130. In other embodiments there slidable spring assembly utilizes only a compression spring 130 and a support pad 128. In other embodiments the spring housing 132 may take any configuration. For instance, the spring housing 132 may only be a top section which extends through the slot 142 and does not have any sides covering the spring.

Disposed between the left handle body 138 and right handle body 140 is a slot 142. The slot 142 is an opening in the top of the tensioner 100. The top of the spring housing 132 extends through the slot 142. A user can slide the spring housing 132 back and forth through the slot 142 to set the slidable spring assembly to the proper position along the lever 108. By moving the slidable spring assembly along the lever 108 the user sets the proper tension amount.

Connected to the lever 108 is a cam assembly. The cam assembly comprises a cam 120, a stop 144, an axial spring 126, an axial spring plate 124, and a pin 122. The cam 120 is connected to the lever 108 by and axel (not shown) and the axial spring 126. The axial spring plate 124 holds the pin 122 in place and assists with guiding the brake lever 110. The cam 120 has a recess set in the body of the cam which fits the stop 144. When the lever 108 is lifted with sufficient force to overcome the tension established by the slidable spring assembly, the stop 144 is disengaged from the cam 120. The axial spring 126 then causes the cam 120 to rotate. The diameter of the cam 120 varies around the cam 120, increasing in diameter in the direction that the cam 120 rotates. Resting on top of the cam 120 is one end of the brake lever 110. The rotation of the cam 120 causes the end of the brake lever 110 to be pushed upward by the increasing diameter of the cam 120. In addition, the pin 122 is also attached to the cam 120. The pin 122 is an elongate member and may be any size and shape. The pin 122 has a first end and a second end. The first end of the pin 122 is connected to the cam 120. In the preferred embodiment, the second end of the pin 122 has a bend. As illustrated in FIG. 5 the pin 122 rests between the lever 108 and the brake lever 110. When the cam 120 turns, the cam 120 pushes the second end of the pin 122 towards the disk brake 114. The bend of the pin 122 supports the braking end of the brake lever 110 when the brake lever 110 is disengaged from the disk brake 114. In this manner the pin 122 stabilizes the end of the brake lever 114 to prevent the brake lever 114 from wobbling and causing the tension to accidentally lock in place.

The separate components utilized are illustrated in the drawings are shown in their preferred embodiments though other embodiments may be utilized without varying from the scope of the invention. The lever 108 may be any size, shape, and configuration. In the preferred embodiment, one end of the lever 108 is shaped to define an aperture. The aperture permits the lever 108 to be rotably connected to the disk brake 114 and rotate about the axle 104. In other embodiments the lever 108 may have a hole placed in the body of the lever 108 or the aperture. In the preferred embodiment the lip 116 and the channel 112 are smooth and straight surfaces to permit the easy movement of the disk brake 110 along the lip 116. In other embodiments the lip 116 and/or the channel 112 may have teeth or jags similar to gears to help with the locking mechanism.

In the preferred embodiment the tension placed on the string is placed by user motion of the tensioner 100. In other embodiments the racket stringing machine may have a motor to move the tensioner 100. In other embodiments the lip 116 may be disposed on a longitudinal component extending the length of the tensioner 100. The brake lever 110 would be configured to slide along the length of the lip 116 when the brake lever 110 is perpendicular to the lip 116. The opposite end of the brake lever 110 is attached to the string gripper. When the proper tension is reached, the brake lever 110 alters its angle away from perpendicular and is locked in place on the lip 116.

In another embodiment of the invention, the spring 130 is fixed in place on the tensioner 100. The spring 130 is disposed between the lever 108 and the internal compartment of the tensioner 100. The spring 130 may be at a preset tension. In another embodiment the spring 130 is connected to an external knob. The user may turn the knob to turn one end of the spring 130. The other end of the spring 130 is fixed in place. In this manner the tension of the spring 130 may be altered. While in use, the movement of the tensioner 100 away from the racket provides tension to the string. When the tension in the string equals the force of the spring 130, the tensioner 100 stops rotating and the user can tie the string off in place on the racket.

There are several different embodiments of the invention. In one embodiment the self-locking tensioner and disk brake is used on a tensioner which utilizes a drop weight to create tension in the string. In other embodiments the disk brake mechanism is used on a tensioner which utilizes a crank system to create tension in the string. In this manner the braking mechanism can be utilized with any tennis racket stringing machine which creates tension in the string through any mechanical means.

What has been described above includes examples of the claimed subject matter. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the claimed subject matter, but one of ordinary skill in the art can recognize that many further combinations and permutations of such matter are possible. Accordingly, the claimed subject matter is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.

The foregoing method descriptions and the process flow diagrams are provided merely as illustrative examples and are not intended to require or imply that the steps of the various embodiments must be performed in the order presented. As will be appreciated by one of skill in the art the order of steps in the foregoing embodiments may be performed in any order. Words such as “thereafter,” “then,” “next,” etc. are not intended to limit the order of the steps; these words are simply used to guide the reader through the description of the methods. Further, any reference to claim elements in the singular, for example, using the articles “a,” “an” or “the” is not to be construed as limiting the element to the singular.

The preceding description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the following claims and the principles and novel features disclosed herein. 

1) A tensioner arm for a racket stringing machine comprising a) a tensioner housing; b) a lever disposed in said tensioner housing; c) a drum connected to said lever; d) a string gripper connected to said drum; e) a compression spring disposed between said lever and an internal portion of said tensioner housing. 2) The tensioner arm as in claim 1 further comprising a slidable spring assembly a) wherein said tensioner housing has an elongated slot in one side; b) wherein said compression spring is disposed in said slidable spring assembly; c) wherein a portion of said slidable spring assembly extends through said elongated slot. 3) The tensioner arm as in claim 2 wherein said slidable spring assembly further comprises a) a spring housing; and b) a spring support pad disposed at an end of said compression spring and wherein said spring support pad is disposed adjacent to said lever. 4) The tensioner as in claim 1 further comprising a) a disk brake having an axle extending from an axis of said disc brake; i) wherein said disk brake is connected to a stringing machine body and is rotably stationary relative to said stringing machine body; ii) wherein said disk brake has a lip disposed laterally from said disk brake; b) a brake lever disposed in said tensioner housing; i) wherein said brake lever has a first end and a second end, said first end having a channel disposed laterally into said brake lever; c) wherein said lever has a first end and a second end, said first end having an aperture; d) wherein said axel of said disk brake is disposed through said aperture of said lever; and e) wherein said lip of said disk brake is disposed within said channel of said brake lever. 5) The tensioner as in claim 4 further comprising a cam a) wherein said cam is connected to said lever; b) wherein said cam has a varying diameter about said cam; c) wherein an external perimeter of said cam is adjacent to said second end of said brake lever; d) wherein when said cam rotates about a cam axis, said external perimeter of said cam displaces said second end of said brake lever. 6) The tensioner as in claim 5 further comprising an axial spring having a first end connected to said lever and a second end connected to said cam. 7) The tensioner as in claim 6 further comprising a stop connected to said tensioner housing wherein said stop is disposed within a notch in said cam, preventing said cam from rotating about said cam axis when said stop is disposed within said notch. 8) The tensioner as in claim 7 further comprising a pin having a first end connected to said cam and a second end disposed adjacent to said first end of said brake lever. 9) An automatically braking tensioner for a racket stringing machine comprising a) a tensioner housing; b) a drum; c) a string gripper connected to said drum; d) a disk brake having an axle extending from an axis of said disc brake; i) wherein said disk brake is connected to a stringing machine body and is rotably stationary relative to said stringing machine body; ii) wherein said disk brake has a lip disposed laterally from said disk brake; iii) wherein said disk brake is disposed within an internal cavity of said drum; e) a lever disposed in said tensioner housing; i) wherein said lever has a first end and a second end, said first end having an aperture; ii) wherein said axel of said disk brake is disposed through said aperture; f) a brake lever disposed in said tensioner housing; i) wherein said brake lever has a first end and a second end, said first end having a channel disposed laterally into said brake lever; g) wherein said lip of said disk brake is disposed within said channel of said brake lever. 10) The tensioner as in claim 9 further comprising a cam a) wherein said cam is connected to said lever; b) wherein said cam has a varying diameter about said cam; c) wherein an external perimeter of said cam is adjacent to said second end of said brake lever; d) wherein when said cam rotates about a cam axis, said external perimeter of said cam displaces said second end of said brake lever. 11) The tensioner as in claim 10 further comprising an axial spring having a first end connected to said lever and a second end connected to said cam. 12) The tensioner as in claim 11 further comprising a stop connected to said tensioner housing wherein said stop is disposed within a notch in said cam, preventing said cam from rotating about said cam axis when said stop is disposed within said notch. 13) The tensioner as in claim 12 further comprising a pin having a first end connected to said cam and a second end disposed adjacent to said first end of said brake lever. 14) The tensioner as in claim 13 further comprising a) a slidable spring assembly; b) a slot disposed in said tensioner housing; c) wherein said slidable spring assembly is configured to slide along a length of said lever; d) wherein a portion of said slidable spring assembly extends through said slot. 15) The tensioner as in claim 14 wherein said slidable spring assembly further comprises a) a spring housing; b) a compression spring disposed within said spring housing; c) a spring support pad disposed at an end of said spring and wherein said spring support pad is disposed adjacent to said lever. 16) The tensioner as in claim 15 wherein said cam further comprises a brake release extending from said cam and disposed through an aperture in said tensioner housing. 17) A racket stringing machine comprising a) a machine base; b) a rotational plate base attached to said machine base; c) a self-locking tensioner attached to said machine base, wherein said self-locking tensioner further comprises i) a tensioner housing; ii) a drum; iii) a string gripper connected to said drum; iv) a disk brake having an axle extending from an axis of said disc brake; (1) wherein said disk brake is connected to a stringing machine body and is rotably stationary relative to said stringing machine body; (2) wherein said disk brake has a lip disposed laterally from said disk brake; (3) wherein said disk brake is disposed in an internal cavity of said drum; v) a lever disposed in said tensioner housing; (1) wherein said lever has a first end and a second end, said first end having an aperture; (2) wherein said axel of said disk brake is disposed through said aperture; vi) a brake lever disposed in said tensioner housing; (1) wherein said brake lever has a first end and a second end, said first end having a channel disposed laterally into said brake lever; vii) wherein said lip of said disk brake is disposed within said channel of said brake lever. 18) The racket stringing machine as in claim 17 wherein said self-locking tensioner further comprises a cam a) wherein said cam is connected to said lever; b) wherein said cam has a varying diameter about said cam; c) wherein an external perimeter of said cam is adjacent to said second end of said brake lever; d) wherein when said cam rotates about a cam axis, said external perimeter of said cam displaces said second end of said brake lever. 19) The racket stringing machine as in claim 17 wherein said self-locking tensioner further comprises an axial spring having a first end connected to said lever and a second end connected to said cam. 20) The racket stringing machine as in claim 18 wherein said self-locking tensioner further comprises a stop connected to said tensioner housing wherein said stop is disposed within a notch in said cam, preventing said cam from rotating about said cam axis when said stop is disposed within said notch. 